A process for the preparation of thiophosphoryl chloride is known in the art. British Patent 694,380 discloses the preparation of thiophosphoryl chloride (PSCl.sub.3) by refluxing phosphorous trichloride (PCl.sub.3) and excess sulfur at atmospheric pressure, in the presence of carbon (activated with K.sub.2 S) and about 40 mole percent of thiophosphoryl chloride for about three hours. German Patent 1,145,589 discloses that thiophosphoryl chloride is obtained by treating phosphorous trichloride and sulfur in liquid phase at atmospheric pressure, using aluminum or alloys thereof, preferably aluminum wastes, as a catalyst. Thiophosphoryl chloride is preferably used as the reaction medium and moderator. Further, U.S. Pat. No. 5,464,600 discloses that thiophosphoryl chloride is obtained by reacting phosphorous trichloride and sulfur in the presence of a catalytic amount of a tertiary amine.